216 



BULLETIN 68. 



in the spring, in the same manner as practiced with grape cuttings 

 in the West. It grafts readily on several of our common poplars 

 and on strong growing kinds its growth is considerably increased. 

 "P. alba var. argentea closely resembles the species but has 

 heavier down on the underside, and is rather more spreading in 

 habit, and is more easily propagated from cuttings." 



II. THE CULTIVATED SPECIES OF POPLARS. 



The following catalogue attempts to refer the nursery and horti- 

 cultural names of pop- 

 lars to their proper 

 botanical species, and 

 it includes various 

 notes upon the horti- 

 cultural values of the 

 different types. The 

 genus appears to be 

 much confused 

 amongst nurserymen, 

 and the perplexity has been 

 increased by the arrival of the 

 Russian varieties. In the pre- 

 paration of this monographic list, 

 I have received the greatest aid 

 from the collection of EHwanger & 

 Barry, which has been freely placed at 

 my disposal. The winter twigs are often 

 useful in distinguishing the species, and I 

 have therefore inserted a photograph (Fig. i) 

 of some of them. 



GROUP I. BALSAM POPLARS, or those with 

 resinous-sticky more or less elongated buds. 



i. Populus angfustifolia (James, Long's 

 Exped. i-497). YELLOW or BLACK POPLAR of 

 the west. Fig. 2. A pyramidal small tree with 

 ovate-lanceolate willow-like leaves and cylindri- 

 cal twigs, native from South Dakota west and south. It is spar- 

 ingly cultivated. It is a tree of good habit and soft clear green 



2. Populus angus- 

 tifolia. (% nat. 

 size. ) 



